Vania



R. A. PARKE. -FLUID PRESSURE BRAKE APPARATUS.

No. 553,475? Patented Jan. 21. 1896.

(No Model) i WITNESSES:

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NlTE STATES PATENT OFFICE.

ROBERT A. PARKE, OF NElV BRIGHTON, NEW YORK, ASSIGNOR TO THE VESTINGHOUSE AIR BRAKE COMPANY, OF \VILMERDING, PENNSYL VANIA.

FLUiD-PRESSURE BRAKE APPARATUS.

SPECIFICATION forming part of Letters 1? Application filed May 2]., 1895- To all whom it may concern.-

Be it known that 1, ROBERT A. PARKE, a citizen of the United States, residing at New Brightoinin the county of Richmond and State of New York, have invented or discovered a certain new and useful Improvement in Fluid- Pressure Brake Apparatus, of which improvement the following is a specification.

The object of my invention is to provide an improvement in fluid-pressure brake apparatus for controlling the application of the brakes on railway-cars; and to this end my invention consists in a new and improved triple-valve device for effecting the application of the brakes in service applications by a comparatively slow movement of the triplevalve piston, consequent on a gradual reduction of train-pipe pressure, and in emergency applications by a rapid movement of the triple-valve piston, consequent on a sudden reduction of train-pipe pressure; in means by which both the service and emergency applications of the brakes are controlled by the main valve of the triple-valve device; and, further, in means for imparting to the main valve a greater movement in emergency applications than in service applications without a corresponding increase in the travel of the triple-valve piston.

By means of my improvement the main valve is moved in service applications by contact with the main valve of parts secured to or formed on the stem of the triple-valve piston, and in emergency applications the main valve is given a greater movement, and this greater movement is caused by an increase of pressure which is effected by the rapid movement of the triple'valve piston.

The accompanying drawing is a central longitudinal section through a triple-valve device constructed in accordance with my invention.

The casing 1 of the triple-valve device is connected by means of the screw-threaded nozzle 2 with the train-pipe or with a branch pipe therefrom, and the piston-chamber 3 is in open communication with the train-pipe through the passages 4 and 5 in the casing 1, and through the chamber 6 in the cap 7, which is bolted to the end of the casing. The piston 8 of the triple-valve device is provided mm No. 553,475, dated January 21, 1896.

$ erial No- 550,055\ (No model.)

with a cylindrical tubular extension 9, which is fitted in the bushing 10 of the valve-chamber 11. The stem 12 of the triple-valve piston may be formed integral with or secured to the piston 8, or to the tubular extension 9, in any suitable manner. As shown in the drawing, it is connected to the extension 9 by means of arms or webs 14, which are formed integral with the extension 9 and with an enlargement 13 of the stem, so that the piston S, the extension 9, and the stem 12 form a single integral structure.

The main valve 15 of the triple-valve device is provided with a normally-closed cylindrical chamber 16, to one end of which is fitted a screw-threaded cap or head 18. The stem 12 passes through the cap or head 18 and projects into the chamber 16 of the valve 15. A piston 17, which is fitted to slide in the chamber 16, is secured by a screw-thread connection to the end of the stem 12, and when the parts are in the positions shown in the drawing the spaces within the chamber 16 on opposite sides of the piston 17 are in communication with one another through the longitudinal passage 29 in the st em 12, and through the transverse passage 28 in the stem, which connects the passage 29 with the space outside of and surrounding the stem.

The piston 17 is so fitted in the chamber 16 that when the piston moves slowly in the cylinder the fiuid on the side toward which the piston is moving may pass around the piston to the other side and permit an equalization of the pressures on the two opposite sides without effecting any considerable compression of the fluid or any movement of the valve 15, the movement of the valve 15 being resisted by the friction of the valve on its seat. \Vhen the piston is moved slowly to the left as in service applications, no movement of the valve 15 will be eifected until the piston 17 comes in contact with the cap or head 18.

The passage through which the fluid passes from one side of the piston 17 to the other side when the port 28 has been moved into or to the left of the cap 18 may be formed around the piston 17 by making the piston fit loosely in the chamber 16, or one or more passages may be formed through the piston in contact with the cap 18.

or in the wall of the piston-chamber. The capacity of the passage or passages by means of which equalization of the pressures on opposite sides of the piston is permitted when the piston moves slowly is so limited, however,that when the piston 17 is moved quickly, as by a sudden and considerable reduction of train-pipe pressure, the fluid in that end of the chamber toward which the piston is moving cannot escape to the other side of the piston with sufficient rapidity to prevent an increase of pressure between the piston 17 and the head of the cylinder or chamber 16 toward which the piston is moving, and the pressure between the piston 17 and the cap or head 18 will cause the valve 15 to move to the left before the piston 17 comes in contact with the cap or head 18.

The main valve 15 is provided with a cavity 22;, through which fluid from the brakecylinder is exhausted to the atmosphere when the brakes are released, and with a port or passage 30, extending from the chamber 16 tov the face of the valve 15, in position to be closed when the valve is in release position and to be opened to the brake-cylinder when the valve is moved to the left.

\Vhen the parts are in the positions shown in the drawing, which positions they will occupy when the brakes are released, the triplevalve piston 8 uncovers the feed-groove 19 and fluid from the train-pipe flowsv through the feed-groove 19, around the piston 8 and through the passage 20 to the auxiliary reservoir. The main valve 15 is then in position to release the brakes, the brake-cylinder passage 21 being connected by means of the cavity 2 2 with the exhaustpassages 23 and 24, which lead to the atmosphere.

The valve-chamber 11 is at all times in open communication with the auxiliary reservoir through a comparatively small passage 25, which opens at one end into the chamber 11 and at the other end either directly into the auxiliary reservoir or into. a chamber or passage which is in opencommunication with the auxiliary reservoir.

The capacity of the passage 25 should be equal to or a little greater than the capacity of the smallest of the passages 28, 29, and 30, through which fluid from the auxiliary reservoir is admitted to the brake-cylinder in service applications.

The enlargement 13 of the stem 12 forms a shoulder which is provided with a packing 26., adapted to bear against the annular edge of the screw-cap 18 to form a tight joint and thereby prevent the passage of fluid from the chamber 11 into the chamber 16.

When a comparatively slight and gradual reduction of train-pipe pressure is made for the purpose of effecting a service application of the brakes the piston 8, the stem 12, and the piston 17 will move to the left, without moving the valve 15, until the piston 17 comes The packing 26 on the enlargement 13 of the stem 12 then,

will have moved away from the cap 18 a distance equal to the stroke of the piston 17 in the chamber 16, and the port 28, which extends through the stem 12 and connects with the passage 29 in the stem, will have moved through and to the left of the cap 18, and will be open to the chamber 11, so as to be in position to permit the auxiliary-reservoir fluid in said chamber 11 to pass through the passage 29 into the chamber 16. As the piston 8 continues its movement after the piston 17 has come in contact with the cap 18, the valve 15 will be moved to the left until the piston 8 has completed its stroke and bears against the gasket 27. The movement of the valve 15 to the left will first cut off communication between the brake-cylinder passage 21 and the exhaust-passages 23 and 24, and then open communication between the brakecylinder passage 21 and the passage 30 in the valve 15. The valve-chamber 11, which is always in communication with the auxiliary reservoir through the passage 25, will then be in communication with the brake-cylinder and auxiliary-reservoir fluid will flow through the passages 28 and 29 in the stem 12,through the chamber 16 to the right of the piston 17, and through the passages. 30 and 21 to the brake-cylinder, and the brakes will be applied. The auxiliary-reservoir pressure will be reduced by expansion into the brake-cylinder, and if the reduction of train'pipe press.- ure is not continuous the pressure in the auxiliary reservoir will be reduced below that in the train-pipe. hen the auxiliary-reservoir pressure becomes slightly less than that in the train-pipe, the piston 8 and the stem 12 will be moved back to the right until the packing 26 on the enlargement 13 bears of fluid around the stem 12 from the auxiliary reservoir. A further reduction of train-pipe pressurebelow that in the auxiliary reservoir will again. cause the piston 8 to move to the left and open the port 28 to admit fluid from the auxiliary reservoir to the brake-cylinder, and when the auxiliary-reservoir pressure again falls below the train-pipe pressure the piston 8 and stem 12 will be moved to the right to close port 28 and cut off communicationbetween the auxiliary reservoir and the brakecylinder. This operation may be repeated until the desired pressure is obtained in the brake-cylinder, or until the auxiliary-reservoir and brake-cylinderpressures have equalized. In case the reduction of train-pipe pressure is continuous, or such as to keep the train-pipe pressure somewhat below that in the auxiliary reservoir during the whole of the application, the piston 8 may be held to the limit of its stroke to the left and the port 28 kept continuously open to admit fluid from the auxiliary-reservoir to the brake-cylinder until the brakes are fully applied, or until the auxiliary-reservoir and brake-cylinder pressures have equalized.

A comparatively large passage 31 extends through the triple-valve piston 8 and is controlled by a valve 32 provided with a stem 33, which projects into and is guided by a tubular extension 34 of the piston-stem 12. A spring 35, which tends to hold the valve 32 to its seat, surrounds the stem 33 and the tubular extension 3i and bears at one end against the valve 32 and at the other end against the enlargement 13 of the stem 12.

When a sufficiently great and sudden reduction of train-pipe pressure occurs, such as is necessary to effect an emergency application of the brakes, the piston 8 will be suddenly moved to the limit of its stroke to the left and with it the piston 17 on the stem 12. The fluid in the chamber 16 between the piston 17 and the head 18 will not have time to escape to the right of the piston 17 before the piston 8 makes its full stroke, and the piston 17 will not come in contact with the cap or head 18; but the pressure of the compressed fluid between the piston 17 and the cap or head 18 will cause the valve 15 to begin its movement when the piston 17 has moved only a part of the distance which it travels relative to the valve 15 in service application.

The sudden movement of the pistons 8 and 17 will not only effect an earlier movement of the valve 15, but the valve 15 will be moved farther to the left than it is in service applications. The additional movement of the valve 15 beyond that which it makes in service applications will be equal to the distance between the piston 17 and the cap or head 18 when the piston 8 reaches the end of its stroke, and will bring the right-hand end of the valve 15 far enough to the left to uncover a large part of the port or opening 36 between the chamber 11 and the passage 21 leading to the brake-cylinder.

The sudden opening of a large passage leading from the chamber 11 to the brakecylinder will cause a sudden and great reduction of pressure in the chamber 11, because the capaeity of the port or opening 36, through which the fluid escapes to the brakecylinder, is very much greater than the capacity of the passage 25 which connects the chamber 11 with the auxiliary reservoir. This reduction of pressure in the chamber 11 will be sufficient to permit the train-pipe press-.

ure to lift the valve 32 from its seat, and fluid from the train-pipe will then flow through the passage 31, chamber 11, port 36, and passage 21 to the brake-cylinder, until the pressure in the brake-cylinder is nearly equal to that in the train-pipe, when the valve 32 will close and prevent a return flow from the brakecylinder and chamber 11 to the train-pipe.

' The exhaust of fluid from the train-pipe to the brake-cylinder will require but a very short time on account of the large capacity of the passages 31, 36, and 21, and will take place before any considerable amount of fluid can flow from the auxiliary reservoir through the passage 25. After the release of fluid from the train-pipe takes place, fluid from the auxiliary reservoir will flow through the passage 25, chamber 11, port 36, and passage 21 to the brake-cylinder, until the auxiliary-reservoir and brake-cylinder pressures have equalized.

, The exhaust of fluid from the train-pipe on each car to the brake-cylinder not only causes the brakes to be applied with greater force than in service applications, but also causes a quicker action of the brakes on the next car and an almost simultaneous action of all of the brakes on the train.

If it is considered undesirable that the piston 17 should come in direct cont-act with the cap or head 18, a collar or other projecting part may be secured to the stem 12 to the left of the piston 17 in position to come in contact with the cap or head 18 when the piston is moved to the left. The distance between such collar or projecting part and the cap 18 will of course be such as to give the proper movement to the valve 15. The piston 17, either with or without the collar or projection on the stem, may be formed integral with that portion of the stem which projects into the chamber 16, and a screw-threaded or other connection will then be necessary to connect ICO that portion of the stem with the enlargement 13.

I claim as my invention and desire to secure by Letters Patent-- 1. The combination, in a triple valve device, of a main valve; a piston whose movement effects the operation of the main valve, and which has the same traverse in both service and emergency applications, and means whereby an increase of pressure, caused by a rapid movement of the piston, operates the main valve to cause an emergency application of the brakes, substantially as set forth.

2. The combination, in a fluid pressure brake apparatus, of a valve controlling the release of fluid from the train pipe in emergency applications of the brakes, a chamber in a casing which is formed on or connected to the valve, av piston in the chamber and a main piston which has the same traverse in both service and emergency applications, which is operated by variations of train pipe pressure, and which is adapted, when moved rapidly by a sudden reduction of train pipe pressure, to eflect an increase of pressure in the chamber and thereby cause a movement of the valve into position to effect an emergency application of the brakes, substantially as set forth.

3. The combination, with a triple valve piston which'has the same traverse in service and emergency applications, of a valve controlling the release of fluid from the train IIO pipe, a chamber in a casing which is formed on or connected to. the valve, and a piston in the chamber which is connected to and operative by the triple valve piston, and which is adapted, when moved rapidly, toeifect an increase of pressure in that end of the chamber toward which it is moving, and thereby to cause the valve to move into position to pressed b y-a rapid movement of the piston so.

as to move the valve into position to. effect an emergency application of the brakes, substantially as set forth.

5. The combination, in a triple valve device, of a main valve, a chamber in a casing formed on or connected to the main valve, and a piston in the chamber which is adapted to move the valve by direct contact, of the piston or its stem with the valve or the wall of the chamber, in making service applications of the brake, and which effects a greater movement of the valve in emergency applications, by means of the pressure of the fluid between the piston and the end of the chamber when the piston is moved rapidly by a sudden reduction of train pipe pressure, substantially as set forth.

6. The combination in a triple valve device, of a triple valve piston, a main valve, a chamber in a casing which is formed on or connected to the main valve, a supplemental piston in the chamber which is connected to and operated by the triple valve piston, a passage in the stem through which fluid under pressure is admitted from the auxiliary reservoir to one end of the chamber and a port or passage through the main valve which is adapted to form a communication between the chamber and the brake cylinder in applications of the brakes, substantially as set forth.

In testimony whereof I have hereunto set my hand.

ROBERT A. PARKE.

\Vitnesses:

A. B. DAVIS, W. L. MURRAY. 

